Conventionally, a variety of display panels each include a display unit that is sealed by two substrates facing each other via a sealing material have been put into practical use. Examples of such display panels include an organic electroluminescence (EL) display panel having organic electroluminescence elements in the display unit, and a liquid crystal display panel having liquid crystal elements in the display unit.
Patent Literature (PTL) 1 discloses an organic EL display device (display panel) in which an element substrate on which organic EL layers are formed is sealed by a sealing substrate via a sealing portion. In the organic EL display device, sealing the element substrate by the sealing substrate at a pressure higher than the atmospheric pressure causes both the element substrate and the sealing substrate to curve so as to be outwardly convex (in other words, the display panel expands) under the atmospheric pressure. Such a curved shape of the above organic EL display device can prevent deterioration of the elements due to an external pressure.
PTL 2 discloses an organic EL device including: a seal member having at least one sealing port and arranged between an array substrate and a sealing substrate; and a resin layer arranged inside the seal member. In the aforementioned organic EL device, an excess resin inside the seal member is discharged from the sealing port when sealing is performed. Such a sealing port in the aforementioned organic EL device reduces a load applied to the seal member, thereby preventing breakdown of the seal member.